Seamie Heffernan has been studying old renewals of the Prix de l'Arc de Triomphe in an attempt to plot the best path to success on So You Think at Longchamp on Sunday. Tha star colt drew 14 of the 16 runners.

The question that seems to be on the lips of every pundit is whether Aidan O'Brien's giant Australian import will be as effective over a mile and a half, given all his best form in Ireland is over 10 furlongs.

The affable Heffernan has been on board for his wins in a Group Three at the Curragh, the Eclipse and Irish Champion Stakes, and he is excited by the prospect of riding him in Europe's biggest race.

He said: "I've only ever ridden him over a mile and a quarter and I've been very happy with him over that trip. The Arc is the Arc and if you don't run them, you don't find out.

"Hopefully everything works out. It's the Arc and it's always going to be a big field with very strong competition. The bigger field might help him, but you never know. He's a very good horse, but you still need a bit of luck on your side and hopefully we get it.

"I remember Mick Kinane's ride on Sea The Stars when he had to sit and suffer when he was waiting for a gap. I've been watching a few of the old Arcs on video and I've ridden in it a few times, so I'm looking forward to it.

"All his preparations have gone very well leading up to it, so this is the big day."

Masked Marvel has been supplemented at a cost of 100,000 euros after winning the Ladbrokes St Leger in great style, and represents John Gosden instead of Nathaniel, who will now wait for the Champion Stakes.

Gosden told Paris-Turf: "His owner, Mr Nielsen, has been very sporting and has accepted supplementation. When we bought Masked Marvel we immediately thought of the St Leger - it's wonderful to see we weren't wrong.

"I have respect for the other contenders but I think the biggest danger in the Arc might have been Pour Moi, who is unfortunately already out to stud. Masked Marvel has made enormous progress."

Prix de l’Arc de Triomphe draw

Stall 1. Hiruno D'amour - Shinji Fujita
Stall 2. Danedream - Andrasch Starke
Stall 3. Testosterone - Stephane Pasquier
Stall 4. Galikova - Olivier Peslier
Stall 5. Masked Marvel - William Buick
Stall 6. St Nicholas Abbey - Joseph O'Brien
Stall 7. Reliable Man - Gerald Mosse
Stall 8. Workforce - Ryan Moore
Stall 9. Shareta - Thierry Jarnet
Stall 10. Meandre - Maxime Guyon
Stall 11. Snow Fairy - Frankie Dettori
Stall 12. Treasure Beach - Colm O'Donoghue
Stall 13. Sarafina - Christophe Lemaire
Stall 14. So You Think - Seamus Heffernan
Stall 15. Silver Pond - Thierry Thulliez
Stall 16. Nakayama Festa - Masayoshi Ebina